AquaCast Mask is a device used for the positioning and immobilization of patient's head undergoing or receiving a course of external beam radiation therapy for the treatment of cancer. Thermoplastic Mask is intended as a single-patient reusable device only and are not sterile.
Device Story
AquaCast Mask is a low-temperature thermoplastic sheet (polycaprolactone) used for patient immobilization during external beam radiation therapy. The sheet is heated (150°F–158°F) to soften, then molded to the patient's head anatomy; it hardens upon cooling to maintain a fixed position. The mask is pre-mounted to a non-patient contacting frame that interfaces with existing clinical support hardware. Used in radiation therapy clinics; operated by healthcare professionals. The device ensures patient stability during treatment, minimizing movement to improve radiation delivery accuracy. It is a single-patient, reusable device.
Clinical Evidence
No clinical data. Bench testing only, including material rigidity (ASTM D790), stretchiness, shrinkage, softening/solidification times, frame compatibility, skin contact temperature, cleaning/disinfection validation, and radiation attenuation (6 MV and 10 MV photons). Biocompatibility testing performed per ISO 10993-1, -5, -10, and -23.
Technological Characteristics
Material: Polycaprolactone thermoplastic. Form factor: Perforated/non-perforated sheets (2.4 mm and 3.2 mm thickness). Softening temperature: 150°F–160°F (65°C–71°C). Rigidity: 1.080 lbs/in². Radiation attenuation: <2%. Biocompatibility: ISO 10993 compliant for surface contact <24 hours. Non-sterile. Mechanical fixation to support hardware.
Indications for Use
Indicated for patients undergoing external beam radiation therapy for cancer treatment requiring head positioning and immobilization.
Regulatory Classification
Identification
A medical charged-particle radiation therapy system is a device that produces by acceleration high energy charged particles (e.g., electrons and protons) intended for use in radiation therapy. This generic type of device may include signal analysis and display equipment, patient and equipment supports, treatment planning computer programs, component parts, and accessories.
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FDA U.S. FOOD & DRUG ADMINISTRATION
September 3, 2025
Blessing Cathay Corporation
Jerry Su
Regulation Affairs Specialist
2F, No. 310, Jianguo 1st Road, Xinzhuang District
New Taipei City, 242047
Taiwan
Re: K252174
Trade/Device Name: AquaCast Mask
Regulation Number: 21 CFR 892.5050
Regulation Name: Medical charged-particle radiation therapy system
Regulatory Class: Class II
Product Code: IYE
Dated: July 11, 2025
Received: July 11, 2025
Dear Jerry Su:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov
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K252174 - Jerry Su
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Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-
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K252174 - Jerry Su
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assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,

Lora D. Weidner, Ph.D.
Assistant Director
Radiation Therapy Team
DHT8C: Division of Radiological
Imaging and Radiation Therapy Devices
OHT8: Office of Radiological Health
Office of Product Evaluation and Quality
Center for Devices and Radiological Health
Enclosure
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| Indications for Use | | |
| --- | --- | --- |
| Please type in the marketing application/submission number, if it is known. This textbox will be left blank for original applications/submissions. | K252174 | ? |
| Please provide the device trade name(s). | | ? |
| AquaCast Mask | | |
| Please provide your Indications for Use below. | | |
| AquaCast Mask is a device used for the positioning and immobilization of patient's head undergoing or receiving a course of external beam radiation therapy for the treatment of cancer. Thermoplastic Mask is intended as a single-patient reusable device only and are not sterile. | | |
| Please select the types of uses (select one or both, as applicable). | ☑ Prescription Use (Part 21 CFR 801 Subpart D)
☐ Over-The-Counter Use (21 CFR 801 Subpart C) | ? |
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BLESSING CATHAY CORPORATION
Bespoke Complete Care to extend quality life
Tel: 886-2-2906-3966
http://www.bcc.taipei
Fax: 886-2-2904-1232
E-Mail: info@bcc.taipei
Address: 2F, No. 310 & 312, Jianguo 1st Road, Xinzhuang District, New Taipei City 242047, Taiwan
# 510(k) Summary
K252174
## 1. Device Submitter
Blessing Cathay Corporation
2F, No. 310, Jianguo 1st Road, Xinzhuang District, New Taipei City 242047, Taiwan
Phone: 886.2.2906 3966 ext. 110
Contact Person:
Jerry Su
Regulation Affairs Specialist
Email: iso@bcc.taipei
Backup Emails: (1) bcc.tw.002@gmail.com (2) ra@bcc.taipei (3) info@bcc.taipei
## 2. Device Name
Device Trade Name: AquaCast Mask
Common Name: Thermoplastic (moldable)
Classification Name: Accelerator, Linear, Medical
Regulation Description: Medical charged-particle radiation therapy system
Regulation Number: 21 CFR 892.5050
Device Class: Class II
Product Code: IYE
Panel: Radiology
## 3. Substantially Equivalent (predicate) device(s)
Device Trade Name: Embrace Thermoplastic
510(k) Number: K120335
Manufacturer: Bionix Development Corporation
## 4. Device Description
AquaCast Mask is used for the positioning and immobilization of patient's head undergoing or receiving a course of external beam radiation therapy for the treatment of cancer. The low temperature thermoplastic
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A
BLESSING CATHAY CORPORATION
Bespoke Complete Care to extend quality life
Tel: 886-2-2906-3966
http://www.bcc.taipei
Fax: 886-2-2904-1232
E-Mail: info@bcc.taipei
Address: 2F, No. 310 & 312, Jianguo 1st Road, Xinzhuang District, New Taipei City 242047, Taiwan
mask is made of AquaCast polycaprolactone sheet for patient immobilization. Heat at a temperature of 150°F ~ 158°F is applied to the sheet to soften it and mold it to the shape of the patient anatomy. The perforated thermoplastic is pre-mounted to a non-patient contacting frame to interface with the user's existing support hardware and hold the patient's head in a fixed position for radiation therapy treatments
# 5. Indication for Use
AquaCast Mask is a device used for the positioning and immobilization of patient's head undergoing or receiving a course of external beam radiation therapy for the treatment of cancer. Thermoplastic Mask is intended as a single-patient reusable device only and are not sterile.
# 6. Technical characteristics
The table below compares technical characteristics of the AquaCast Mask to the Predicate device
| Attribute | Predicate device | Subject device | Comparison and Explanation of Differences |
| --- | --- | --- | --- |
| Trade Name | Embrace Thermoplastic | AquaCast Mask | |
| 510k number | K120335 | NA | |
| Intended Use | Support and immobilize patients receiving external beam radiation therapy | Same as predicate | Equivalent |
| Design | Moldable plastic sheet used for patient immobilization. Heat is applied to the sheet to soften it and mold it to the shape of the patient anatomy. The mask is used for multiple treatments on a single patient. The sheet is pre-mounted to a non-patient contacting frame to interface with | Same as predicate | Equivalent |
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A
BLESSING CATHAY CORPORATION
Bespoke Complete Care to extend quality life
Tel: 886-2-2906-3966
http://www.bcc.taipei
Fax: 886-2-2904-1232
E-Mail: info@bcc.taipei
Address: 2F, No. 310 & 312, Jianguo 1st Road, Xinzhuang District, New Taipei City 242047, Taiwan
| | the user's existing support hardware. | | |
| --- | --- | --- | --- |
| Technology | 1. Perforated plastic sheets that soften for molding when exposed to heat.
2. Fastened to patient support hardware | Same as predicate | Equivalent |
| Composition | Polycaprolactone | Same as predicate | Equivalent |
| Sheet Thickness | 2.4 mm and 3.2 mm | 2.4 mm &3.2 mm | Equivalent |
| Features | Available as perforated and non-perforated sheets | Same as predicate | Equivalent |
| Soften temperature | 160-170° F | 150° ~ 160° F
(65°C~71°C) | The difference does not raise any new risks. |
| Biocompatibility | Limited contact duration (<24 hours) for surface devices (skin). | Same as predicate | Equivalent |
| Sterility | Non-sterile. | Same as predicate | Equivalent |
| Rigidity | 1.080 lbs/in² | Same as predicate | Equivalent |
| Shrinkage | 1.1% | Same as predicate | Equivalent |
| Radiation Attenuation (X-ray) | Less than 2% | Less than 2% | Equivalent |
# 7. Performance data from non-clinical Testing
The FDA under Section 514 of the Food, Drug and Cosmetic Act has not established performance standards for this product
The following non-clinical testing was performed:
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A
BLESSING CATHAY CORPORATION
Bespoke Complete Care to extend quality life
Tel: 886-2-2906-3966
http://www.bcc.taipei
Fax: 886-2-2904-1232
E-Mail: info@bcc.taipei
Address: 2F, No. 310 & 312, Jianguo 1st Road, Xinzhuang District, New Taipei City 242047, Taiwan
| Item | Test method | Test result |
| --- | --- | --- |
| 1. Rigidity of material | ASTM D790 Procedure A | 1.080 lbs/in² |
| 2. Stretchiness of material | The piece are hung and placed in a heating pan at 71°C(160°F) during 31/2~4 minutes, and extension length(Stretched Length in Mm, SLM) is measured after taking out the water. | SLM=100 |
| 3. Shrinkage of material | Test piece is marked with a line to indicate an initial length. When removed from the water bath, the piece is stretched to 70% of the original length and cooled at the fixed stretched position at room temperature (21°C). The distance between two marks is measured in a free position after 24 hours. The shrinkage of the samples at room temperature is calculated in percentage (%) | 0.9% |
| 4. Softening(melting) time/temperature | Turn on heating pan, checking for sufficient water to cover AquaCast Mask. When it has become transparent, record the time period and temperature | 49 ~53 seconds /71°C(160°F) |
| 5. Solidification time/temperature | After AquaCast Mask has become transparent, remove it from heating pan. When it has become hardened, record the time period and temperature | 31/2minutes/25°C(77°F) |
| 6. Holding frame temperature | Prior to placing the softened AquaCast Mask over the patient, test to make sure it is not too warm, and record the temperature | 21°C(69.8 °F) |
| 7. Compatibility with the base plate testing, | Begin by hooking the edge of the thermoplastic sheet under the patient’s chin, with the sheet tilted at a 45° angle to the plane of the face. Stretch the sheet superiorly six to eight inches, and then back down onto the indexing pins on the base plate (Klarity SRS Baseplate,K220539). Rotate the swivel clamps and tighten the screws, fastening the mask in place. Check if the locating pins (9) on the baseplate is fastened tightly. | Pass |
| 8. Thermoplastic-skin contact temperature testing, | Using the transfer sheet remove the sheet from the water and blot off water with a dry towel. Make sure the mask is dry and cool. Record temperature when patient feels comfortable. | 21°C(69.8 °F) |
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A
BLESSING CATHAY CORPORATION
Bespoke Complete Care to extend quality life
Tel: 886-2-2906-3966
http://www.bcc.taipei
Fax: 886-2-2904-1232
E-Mail: info@bcc.taipei
Address: 2F, No. 310 & 312, Jianguo 1st Road, Xinzhuang District, New Taipei City 242047, Taiwan
| 9. Validation of the cleaning | Clean the thermoplastic mask by using soap and water for 10 mins. Check the result. | Pass |
| --- | --- | --- |
| 10. Validation of the disinfection | Isopropyl or an ethanol-based disinfectant is used for the disinfection of thermoplastic mask when applied with a soft cloth. Check the result. | Pass |
| 11. Shrinkage | AquaCast Mask was placed into a heating pan at a temperature of 71°C(160°F) for 3 1/2~4 minutes. AquaCast mask was removed and placed on a phantom head and left to dry. Once dry the mask was measured with a caliper. The mask was again measured after twenty-four hours. The difference in the size would determine the percentage of shrinkage. | 1.5% |
| 12. Radiation Attenuation (X-ray) | Measurements were taken on a Varian Clinic iX linear accelerator, for both 6 and 10 MV photons. Setup was performed 100 cm SAD, using an ion chamber at 10 cm depth of solid water, and 10 cm of solid water underneath. A 10 x10 cm field size was used, and 100 monitor units (MUs) were delivered. Readings were taken using an electrometer. Thermoplastic were in the form of thin uniform sheets, the same previously stated setup was followed, except that a sample of the thermoplastic sheet was placed on top of the solid water so that the field was entirely contained. Like before, 100 MUs were delivered. A attenuation correction factor, AF, was calculated for each thermoplastic sheet. | 6 MV: 0.60%
10 MV: 0.47% |
The patient contact component for the device is the low-temperature thermoplastic mask material, which contacts the skin surface for less than 24 hours. This material has been shown to be biocompatible for the intended use when tested against the requirements of ISO 10993-1, -5, -10 and -23 for cytotoxicity, irritation, and sensitization.
All non-clinical performance testing was completed to ensure that the devices fulfilled that the verification, validation and safety requirements and confirmed that the devices are as safe and effective as the predicate devices.
# 8. Performance data from clinical Testing
No clinical testing was performed in support of this pre-market submission.
{9}
BLESSING CATHAY CORPORATION
Bespoke Complete Care to extend quality life
Tel : 886-2-2906-3966
http://www.bcc.taipei
Fax : 886-2-2904-1232
E-Mail: info@bcc.taipei
Address : 2F, No. 310 & 312, Jianguo 1st Road, Xinzhuang District, New Taipei City 242047, Taiwan
## 9. Conclusion
This device is similar in design, intended use, technological, physical and performance characteristics to the predicate device. No new issues of safety or effectiveness are introduced by using this device. The substantial equivalence comparison in this premarket submission together with the additional provided information has demonstrated substantial equivalence to the predicate device with respect to use, safety and effectiveness for their intended and indicated use.
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.